But if the citizens of a state are to judge and to distribute offices according to merit, then they must know each other’s character: where they do not possess this knowledge, both the election to offices and the decision of lawsuits will go wrong. When the population is very large they are manifestly settled at haphazard, which clearly ought not to be. Besides, in an overpopulous state foreigners and metics will readily acquire the rights of citizens, for who will find them out? Clearly then the best limit of the population of a state is the largest number which suffices for the purposes of life, and can be taken in at a single view.
Aristotle, via breakdown-of-nationsp. 107
also from Rousseau (via a book ostensibly about sex):
If I had had to choose my place of birth, I would have chosen a state in which everyone knew everyone else, so that neither the obscure tactics of vice nor the modesty of virtue could have escaped public scrutiny and judgment.
What allows these chain-linked tragedies is the absence of local, personal shame. The false certainty that comes from applying Malthusian economics, the prisoner’s dilemma, and the tragedy of the commons to pre-agricultural societies requires that we ignore the fine-grain contours of life in small-scale communities where nobody “could have escaped public scrutiny and judgment,” in Rousseau’s words. These tragedies become inevitable only when the group size exceeds our species’ capacity for keeping track of one another, a point that’s come to be known as Dunbar’s number. In primate communities, size definitely matters.
Having evolved in small, intimate bands where everybody knows our name, human beings aren’t very good at dealing with the dubious freedoms conferred by anonymity. When communities grow beyond the point where every individual has at least a passing acquaintance with everyone else, our behavior changes, our choices shift, and our sense of the possible and of the acceptable grows ever more abstract.